PRINCE William's girlfriend has offered to be a mentor to his brother Harry's blonde love, The People can reveal.

Caring Kate Middleton, 24 - seen as the perfect role model - is keen that 20-year-old Chelsy Davy's long-distance relationship with Harry survives.

So she has told the South African beauty: "You can stay at my Chelsea flat anytime you like."

ARoyal source said: "Kate has been particularly good to Chelsy, offering her advice on how to dress and behave at certain functions and giving her tips on how to behavewhen with the princes and their family. The most amazing step is that Kate has told Chelsy she can live with her at her London flat and move her things in if she wants.

"Chelsy often comes to London and it would be useful for her to have a permanent base here."

Wills, 23, and Harry, 21, were seen having fun with their girlfriends at upmarket Boujis club in Kensington on Thursday night. The source added: "No one was sure Kate and Chelsy would get on because they come from different back-grounds.